Alternate push retractable ball pen having double rocking latch mechanism



ug. l, 1959 C. LOCKWOOD ALTERNATE PUSH RETRACTABLE BALL PEN HAVING DOUBLE ROCKING LATCH MECHANISM Filed April 9. 1957 INVENTOR. 'JOHN c. Lockwoo BY /ct/I/wi ALTERNATE PUSH RETRACTABLE BALL PEN HAVING DOUBLE ROCKING LATCH MECH- ANISM John C. Lockwood, Atlanta, Ga., assigner to Scripto, Inc., Atlanta, Ga., a corporation of Georgia Application April 9, 1957, Serial No. 651,648

4 Claims. (Cl. 1Z0-42.03)

This invention relates to ball point writing instruments and more particularly to an improved latch mechanism for a writing instrument of the above character whereby successive depressions of a plunger member alternately project and retract a writing unit.

The present invention comprises a floating latch member arranged between a depressible plunger member and a writing unit and possesses the yadvantages inherent in a floating latch member as described in copending application Serial No. 631,771, filed December 31, 1956. In that application the latch mechanism lis characterized by a single floating latch member adapted for fulcrurnmed rocking in opposite directions in the barrel upon successive depressions of a plunger member.

The present embodiment of a floating latch member is particularly identifiable by a pair of pawl members that are pivotally connected to each other for allowing relative rotation therebetween. This relative rotation allows the floating latch member to be moved forwardly into latching engagement without any rocking or camming action between the contacting surfaces of the plunger member and the latch member. Upon a depression of the plunger member when the writing unit is in re'- tracted position, a first pawl member is rotated relatively to a second pawl member and this allows the rotating pawl member to engage latch engaging means arranged interiorly of the barrel without -any camming or rocking action of the second pawl member which contacts the plunger member. After the first pawl member engages the latch engaging means and the plunger member is released, the second pawl member rocks inwardly of the barrel under the influence of biasing means and is thereby placed in position for engaging a camming face of the plunger member upon the next succeeding depression thereof and allowing the rst pawl member to be disengaged and the writing unit to travel rearwardly to retracted position.

These and other features of the present invention are described in further detail below in connection with the drawings, in which:

Fig. l is a central, longitudinal cross section of the writing instrument according to the present embodiment of the invention and showing the writing unit in projected position;

Fig. 2 is a transverse cross section taken along the lines 2 2 of Fig.v l;

Fig. 3 is a partial, longitudinal cross section, 180 from the View of Fig. l, showing the operating mechanism in the position it occupies when the writing unit is retracted;

Fig. 4 is a partial, longitudinal cross section, 180 from the view of Fig. l, showing the operating mechanism in the position it occupies when the plunger is depressed from the position shown in Fig. 3 for projecting the writing unit from the barrel and prior to the engagement of the latch means with the latch engaging means as shown in Fig. l; and

Fig. 5 is a partial, longitudinal cross section, 180

2,898,886 Patentedug. 11, 1959 from the view of Fig. 1, showing the operating mechanism with the plunger member fully depressed from the position shown in Fig. 1 and the latch means in position for clearing the latch engaging means.

The writing instrument indicated generally by the numeral 10 comprises a two-part barrel housing formed by forward barrel portion 12 and rear barrel portion 14. Within the barrel portion 12, a writing unit 16 is slidably arranged for projection forwardly to -a writing position thro-ugh the tapered writing tip of the forward barrel portion 12 and is biased rearwardly for retraction therein by barrel spring 18 which is seated on inwardly stepped annular shoulder 20 formed adjacent the forward end of the barrel portion 12 and which bears against shoulder 22 formed exteriorly on the writing unit 16.

The forward barrel portion 12 is reduced in diameter and threaded adjacent its rear end as indicated at 24 for assembly with rear barrel portion 14 which is fitted for this purpose with an internally threaded assembly cap 26. The assembly cap 2.6 has an aperture 28 extending therethrough to allow rearward extension of the writing unit 16 into the rear barrel portion 141. The rear end of the writing unit 16 is fitted with a cartridge plug 30 having an aperture 32 extending therethrough and a cover cap 34 is provided about the upper portion of the cartridge plug 30. It will be noted that atmospheric pressure is admitted to the upper portion o-f the ink column by means of exterior grooves provided in the outer walls of the cartridge plug 30 in communication with aperture 32'. This feature also provides leakproof protectio-n as is described in detail in copending application Serial No. 476,479, tiled December 20, 1954. A suitable follower 36 is provided within the writing unit 16 to provide meniscus stability since the ink reservoir 37 chosen for illustration is noncapillary in diameter. It is, of course, understood that an ink reservoir 36 of capillary size could be employed.

A mechanism housing 38 is arranged within the rear barrel portion 14 and is fixed to the barrel by an inwardly turned dimple 4t) on rear barrel 14 which passes through a locking aperture 42 in mechanism housing 38. A plunger member 44 is slidably arranged within the mechanism housing 38 and is provided with a rearwardly facing stop shoulder 46 adapted for abutting a stop face 48 on mechanism housing 38 thereby restricting the rearward movement of plunger member 44.

Referring now to Fig. 2, a U-shaped latch guide member 50 is shown fitted to mechanism housing 38 -so that its base portion is positioned between rear barrel portion 14 and mechanism housing 38, and laterally extending guide rails 52 on either side of guide member Sil pass through slots 54 arranged in mechanism housing 38; latch guide member 50 being further formed with a protruding latch lug 56 extending perpendicularly to the axis of the barrel through an aperture in mechanism housing 38 and forming latch engaging means for latch means 57. The latch guide member rails 52 extend forwardly from the latch engaging means 56 a suicient distance to provide a channel in which latch means 57 is guided during .the projection and retraction of the writing unit 16.` The forward portion of one of the guide rails 52 is inwardly turned to form a retaining stop 58 for the latch means 57 to restrict the forward motion of latch means 57 when rear barrel portion 14 is separated from front barrel portion 12. A clip member 6i) is attached to the outer portion of rear barrel portion 14 and a trim ring 62 is tted over the rear end of rear barrel portion 14; trim ring 62 having an inner configuration which conforms to and is aligned with the mechanism housing 3S to confine plunger member 44 for reciprocal motion therein.

Plunger member 44 is formed forwardly with a transverse latch strike face. 64 joining at one side an upwardly sloping cam face 66 that joins at an opposite side a forward facing curved stop shoulder 68 arranged for receiving the rear portion of latch means`57. Latch means 57 consists of a latch pawl. 72 and a release pawl 74 with latch pawl 72 havingV a pair of spaced pawl faces 76 joined to each other at the forward ends thereof by a base portion forming stop means 78. Release pawl 74 is positioned between the spaced pawl faces 76 and is pivotally connected thereto by pivot pin 80 thereby allowing relative rotation between latch pawl 72 and release pawl 74. This relative rotation is restricted when the forward edge portion 81 of release pawl 74 engages stop means 78.

Release pawl 74 is provided with a rearward extension 82 having a transverse surface 84 adapted for engaging plunger strike face 64 upon alternate depressions of plunger member 44. and a laterally facing camming surface 86 adapted for engaging plunger cam face 66 upon alternate depressions of plunger member 44. Release pawl 74 is further formed with a rearwardly facing reset shoulder 88 adapted for engaging the latch engaging means 56 in the retracted position of the writing unit 16 and with a rearwardly facing spring bearing shoulder 90 arranged on a side of release pawl 74 oppositely from reset shoulder 88. Plunger member 44 also has a spring bearing shoulder 92 facing the release pawl spring bearing shoulder 90 and a bias spring 94 is arranged therebetween rotatably biasing release pawl 74 forwardly and biasing plunger member 44 rearwardly to non-depressed position after each depression thereof.

Latch pawl 72 is provided with laterally disposed arcuate surfaces 95, 96 which are the bearing surfaces for latch means 57 during movement in housing 38 and an extension 97 adapted for engaging latch engaging means 56 in the projected position of the writing unit 16 and for latching the writing unit 16 in projected position. The release pawl 74 is so designed that the forward edge portion 81 thereof will contact inner surface 98 of stop means 78 under the 'bias of spring 94 when latch pawl 72 engages the latch engaging means 56 and plunger strike face 64 is not in contact with surface 84. Further movement of the release pawl 74 after edge portion 81 contacts inner surface 98 of stop means 78 results in a corresponding movement of latch pawl 72 and thus latch pawl 72 is adapted to be released from engagement with stop engaging means 56 upon a sufficient rocking or camming of release pawl 74.

In operation, upon depression of plunger member 44 from the retracted position of the writing unit 16 as shown in Fig. 3, the plunger member transverse strike face 64 contacts the release pawl transverse surface 84 and latch means S7 along with the writing unit 16 is moved forwardly against the bias of barrel spring 18. 'I'he latch pawl extension 97 is cammed inwardly of the barrel upon forward movement of latch means 57 by contact with latch engaging means 56 and thus the stop means 78 on the forward portion of latch pawl 72 is canted in relation to the writing unit 16. Upon the clearing of latch engaging means 56 by llatch pawl 72, latch pawl 72 is rocked outwardly into engagement with latch engaging means 56 under the bias of barrel spring 18 acting through the forward canted surface of latch pawl 72; this bias producing a torque and tending to rock latch pawl 72 in a clockwise direction (see Fig. 5) about pivot pin 80 against the wall of mechanism housing 38. Upon the release of plunger member 44 after latch pawl 72 is in latched position the release pawl 74 is rocked inwardly under the influence of bias spring 94 on the release pawl shoulder 90 until the release pawl edge portion 81 contacts inner surface 98 of stop means 78 on latch pawl 72. Thus, the release pawl cam surface 86 is exposed for camming contact with plunger member 44 as shown in Fig. 1.

Upon the next succeeding depression of plunger memthe release of plunger member 44, the writing unit 16 and latch member 57 are free to travel rearwardly within the barrel to the retracted position of the writing unit 16.

During the rearward travel of the latch means 57 the release latch reset shoulder 88 contacts the latch engaging means S6 thereby restricting the rearward movement of the latch means 57. At this point the latch means 57 is rocked about the latch engaging means 56 under the force of barrel spring 18 acting through the canted stop means 78 until release pawl 74 and latch pawl 72 contact the side of the mechanism housing 38. The plunger member 44 returns to its non-depressed position under the bias of spring 94 and the latch means 57 is in the position shown in Figure 3 whereby a subsequent depression of plunger member 44 will project the writing unit 16 from the forward portion of the writing instrument 10.

The present invention has been described in detail above for the purpose of illustration only, and is not intended to be limited by this description or otherwise except as defined in the appended claims.

l claim:

l. A writing instrument comprising a barrel, a dcpressible plunger slidably disposed within said barrel and projecting beyond the rear barrel end, a writing unit biased rearwardly within the barrel and slidably disposed therein to shift longitudinally between projected and retracted positions with respect to the forward barrel end, a latch means slidably disposed in the barrel between the plunger and writing unit, and means within said barrel laterally offset with respect to said latch means for engagement thereby to latch said writing unit alternatively at said projected and retracted positions, said latch means being unattached to the barrel or writing unit and incorporating a latch pawl member and a release pawl member, said latch pawl member having a body portion bearing rockably at the rear end of said writing unit and a latch pawl portion extending rearwardly therefrom in alignment with said laterally offset barrel means, said release pawl member having a body portion pivoted on said latch pawl `body portion and pivotally associated therewith, said latch pawl body portion having stop means limiting relative pivoting of said release pawl body portion thereon and said latch pawl and release pawl members being thereafter movable as a unit realwardly with respect to said barrel means, said release pawl member further having a release pawl portion extending rearwardly therefrom beyond said latch pawl portion, the body portion of said release pawl member engaging said laterally offset barrel means to determine the retracted position of said writing unit and the rear end of the latch pawl portion engaging said barrel means to determine the projected writing unit position, said depressible plunger being formed for bearing forwardly at the rear end of said release pawl portion upon a rst depression thereof to propel said writing unit and latch means to projected position and engage said latch pawl portion with said barrel means thereat, and said plunger having biasing means arranged to bear therefrom on said release pawl body portion for pivoting said release pawll portion away from said barrel means to the limit allowed on said latch pawl body portion upon engagement of said latch pawl portion at projected position and being further formed for bearing laterally at the rear end of said pivoted release pawl portion upon a succeeding depression thereof to rock said'release pawl mem-ber with said latch pawl member away from said barrel means and thereby disengage said latch pawl portion and permit retraction of said latch means and writing unit, said pivoted release pawl portion being returned to its original position against the force of said plunger biasing means by engagement of said release pawl body portion at said barrel means upon retraction of said latch means and writing unit under the force of said rearwardly biased writing unit.

2. A writing instrument comprising a barrel, a depressible plunger slidably disposed within said barrel and projecting beyond the rear 'barrel end, a writing unit biased rearwardly within the barrel and slidably disposed therein to shift longitudinally between projected and retracted positions with respect to the Iforward barrel end, latch means slidably disposed in the barrel between the plunger and writing unit, and means within said barrel laterally offset with respect to said latch means for engagement thereby to latch said writing unit alternatively at said projected and retracted positions, said latch means being unattached to the barrel or writing unit and incorporating a latch pawl member and a release pawl member, said latch pawl member bearing rockably at the rear end of said writing unit and extending rearwardly in alignment with said laterally offset barrel means, said release pawl member being pivotally associated with said latch pawl member and said latch pawl member having stop means limiting relative pivoting of said release pawl member thereon and said latch pawl and release pawl members being thereafter movable as a unit rearwardly with respect to said barrel means, said release pawl member extending rearwardly beyond said latch pawl member, the rear end of said latch pawl member engaging said barrel means to determine the projected position of said writing unit and said plunger being formed for bearing forwardly at the rear end of said release pawl member upon a iirst depression thereof `to propel said writing unit and latch means to projected position and engage said latch pawl member with said barrel means thereat, and said plunger having biasing means arranged to bear therefrom on said release pawl member for pivoting said member away from said barrel means to the limit allowed on said latch pawl member upon engagement of said latch pawl member at projected position and being further formed for bearing laterally at the rear end of said pivoted release pawl member upon a succeeding depression thereof to rock said release pawl member with said latch pawl member away from said barrel means and thereby disengage said latch pawl member and permit retraction of said latch means and writing unit, said pivoted release pawl member being returned to its original position against the force of said plunger biasing means by engagement of said release pawl member at said barrel means upon retraction of said latch means and writing unit under the force of said rearwardly biased writing unit.

3. A writing instrument comprising a barrel, a depressible plunger slidably disposed within said barrel and projecting beyond the rear barrel end, a writing unit biased rearwardly within the barrel and slidably disposed therein to shift longitudinally between projected and retracted positions with respect to the forward barrel end, latch means slidably disposed in the barrel between the plunger and writing unit, and means within said barrel laterally offset with respect to said latch means for engagement thereby to latch said writing unit alternatively at said projected and retracted positions, said latch means being unattached to the barrel or writing unit and incorporating a latch member and a release member, said latch member having a body portion bearing rockably at the rear end of said writing unit and a latch portion extending rearwardly therefrom in alignment with said laterally offset barrel means, said release member having a body portion pivoted on said latch body portion and pivotally associated therewith, said latch body portion having stop means limiting relative pivoting of said release member body portion thereon and said latch member and release member being thereafter movable as a unit rearwardly with respect to said barrel means, said release member further having a release portion extending rearwardly therefrom, the rearwardly extending latch portion of said latch member engaging said barrel means to determine the projected writing unit position and said depressible plunger being formed for bearing forwardly at the rearwardly extending release portion of said release member upon a irst depression thereof to propel said writing unit and latch means to projected position and engage said latch portion with said barrel means thereat, and biasing means bearing on said release member body portion for pivoting said release member rearwardly extending portion to the limit allowed on said latch member body portion upon engagement of said latch portion at projected position, and said plunger being further formed for bearing laterally at the rearwardly extending portion of said pivoted release member upon a succeeding depression thereof to move said release member with said latch member away from said barrel means and thereby disengage said latch portion and permit retraction of said latch means and writing unit, said pivoted release member being returned to its original position against the force of said biasing means by engagement of said release member body portion with said barrel means upon retraction of said latch means and writing unit under the force of said rearwardly biased writing unit.

4. A writing instrument as defined in claim 3 and further characterized in that said plunger has the forward end thereof formed with a square face portion for bearing forwardly at the rear end of said release member to propel said writing unit and an adjacent inclined cam surface for bearing laterally at the rear end of said release member.

References Cited in the le of this patent UNITED STATES PATENTS 2,557,054 Mansheim .lune l2, 1951 2,584,569 Frentzel Feb. 5, 1952 2,734,484 OSullivan Feb. 4, 1956 FOREIGN PATENTS 1,091,302 France Oct. 27, 1954 1,122,125 France Mar. 14, 1956 

